<s>
GNU	B-Language
Gatekeeper	I-Language
(	O
abbreviated	O
as	O
GnuGk	B-Language
)	O
is	O
a	O
free	B-Application
software	I-Application
project	O
that	O
implements	O
an	O
H.323	B-Application
Gatekeeper	I-Application
based	O
on	O
the	O
OpenH323	B-Protocol
or	O
H323Plus	B-Protocol
stack	O
.	O
</s>
<s>
A	O
gatekeeper	O
provides	O
address	O
translation	O
,	O
admissions	O
control	O
,	O
call	O
routing	B-Protocol
,	O
authorization	O
and	O
accounting	O
services	O
to	O
an	O
H.323	B-Protocol
system	O
defined	O
on	O
the	O
H.323	B-Protocol
standard	O
by	O
ITU-T	O
.	O
</s>
<s>
GnuGk	B-Language
's	O
set	O
of	O
features	O
include	O
:	O
</s>
<s>
IPv6	B-Protocol
support	O
(	O
incl	O
.	O
</s>
<s>
It	O
is	O
covered	O
by	O
the	O
GPL-2.0-only	B-License
license	O
.	O
</s>
<s>
Besides	O
,	O
the	O
authors	O
explicitly	O
grant	O
the	O
right	O
to	O
link	O
it	O
to	O
the	O
OpenH323	B-Protocol
and	O
OpenSSL	B-Language
libraries	O
.	O
</s>
<s>
This	O
is	O
necessary	O
,	O
since	O
GNU	B-License
GPL	I-License
is	O
incompatible	O
with	O
the	O
licenses	O
of	O
these	O
libraries	O
.	O
</s>
<s>
At	O
the	O
start	O
of	O
1999	O
,	O
Jan	O
Willamowius	O
convinced	O
the	O
first	O
authors	O
to	O
license	O
their	O
code	O
under	O
GNU	B-License
GPL	I-License
and	O
began	O
the	O
project	O
.	O
</s>
<s>
The	O
code	O
was	O
named	O
OpenH323	B-Protocol
Gatekeeper	O
,	O
short	O
OpenH323GK	O
.	O
</s>
<s>
A	O
team	O
at	O
mediaWays	O
provided	O
LDAP	B-Protocol
subsystem	O
and	O
overlapped	O
sending	O
.	O
</s>
<s>
At	O
the	O
start	O
of	O
2001	O
,	O
Chih-Wei	O
Huang	O
at	O
Citron	O
and	O
his	O
team	O
began	O
to	O
use	O
and	O
modify	O
the	O
project	O
for	O
their	O
VoIP	B-Application
services	O
.	O
</s>
<s>
In	O
2002	O
,	O
GnuGk	B-Language
2.0	O
was	O
released	O
.	O
</s>
<s>
It	O
had	O
new	O
architecture	O
for	O
gatekeeper	O
routed	B-Protocol
mode	O
which	O
can	O
handle	O
thousands	O
of	O
concurrent	O
calls	O
,	O
and	O
introduced	O
full	O
H.323	B-Protocol
proxy	O
and	O
Citron	O
's	O
NAT	O
technology	O
.	O
</s>
<s>
These	O
features	O
made	O
it	O
a	O
carrier-graded	O
H.323	B-Application
gatekeeper	I-Application
suitable	O
for	O
commercial	O
operations	O
.	O
</s>
<s>
To	O
avoid	O
confusion	O
with	O
other	O
OpenH323	B-Protocol
based	O
gatekeepers	O
,	O
the	O
project	O
was	O
renamed	O
GNU	B-Language
Gatekeeper	I-Language
,	O
short	O
GnuGk	B-Language
,	O
to	O
reflect	O
that	O
it	O
was	O
the	O
only	O
gatekeeper	O
available	O
under	O
a	O
GNU	O
license	O
.	O
</s>
<s>
In	O
2006	O
,	O
version	O
2.2.4	O
introduced	O
call	O
failover	O
,	O
ENUM	B-Language
and	O
CLI	O
rewriting	O
.	O
</s>
<s>
In	O
2012	O
,	O
version	O
3.0	O
added	O
IPv6	B-Protocol
and	O
full	O
H.460.18/H.460.19	O
traversal	O
zone	O
support	O
.	O
</s>
<s>
The	O
official	O
website	O
maintains	O
an	O
interoperability	O
list	O
for	O
H.323	B-Protocol
software	O
and	O
products	O
.	O
</s>
<s>
Among	O
the	O
most	O
active	O
were	O
the	O
team	O
a	O
Mediaways	O
(	O
LDAP	B-Protocol
)	O
,	O
Michal	O
Zygmuntowicz	O
(	O
radius	B-Protocol
support	O
)	O
,	O
Chih-Wei	O
Huang	O
(	O
2.2	O
redesign	O
)	O
,	O
and	O
Simon	O
Horne	O
(	O
NAT	O
features	O
)	O
.	O
</s>
